The use of protective helmets by workers in manual timber-cutting is nowadays compulsory for safety. The helmets used in this connection are provided with hinged face shields or visors. A serious problem, which has attracted attention for a long time in connection with such helmets provided with visors in this field, is that saw-dust can get between the helmet and the visor and thus be inhaled or cause serious damage to the eyes of the wearer. Attempts have been made previously to design such a hinged visor so that it in the lowered position can be displaced backwards to sealing engagement with the front edge of the respective helmet. This design requires a fairly complicated mechanism, where the visor is required to be capable of being raised pivotally relative to the helmet as well as being displaceable backwards, which mechanism is thus also somewhat sensitive to disturbances. Furthermore, with the designs previously adopted, in the lowermost sealing position the visor is undesirably close to the wearer's face. Moreover, this solution does not materially eliminate the problem, because even if the entry of dust or the like is prevented when the visor is lowered, it is still possible for dust or other foreign matter to fall down over the face inside the visor, when the visor is raised, for it is not possible to eliminate the risk that saw-dust, conifer needles, twigs, snow, etc. may settle against the upper edge of the visor when this is in its lowered position and is in contact with the front edge section of the helmet.
In another arrangement, proposed in U.S. Pat. No. 3,727,235 a narrow beading of rubber, plastic or similar material, is permanently attached to the upper edge of the visor and is angled in towards the helmet and scrapes against this when the visor is being swung upwards to its raised position. Neither can this proposal give perfectly satisfactory sealing, and furthermore this sealing arrangement requires a rather specialized displaceable frictional attachment of the visor to the helmet. This arrangment cannot be satisfactorily adopted where the visor is merely arranged to be raised and lowered by swivelling around simple pivotal attachments in the helmet.